Although the inclusion criteria were defined inclusively, so that patients with individual clinical criteria of rapid disease progression could have been included, all patients fulfilled the Mayo classification criterion as primary reason for inclusion . Short-term KDIs did not show an acute effect on TKV in either arm. Indeed, dietary interventions in small animals are expected to result in earlier responses than in humans. Interestingly, one patient in the KD group showed a TKV reduction by 8.4% after KD with a return to baseline at the final study visit. This patient was consistently ketogenic throughout the KD and reached peak values for the KD group in acetone measurements. A recent study on intermittent fasting and caloric restriction in obese ADPKD patients showed positive effects with reduction of body weight and reduction of adipose lipid stores correlating with slowed kidney growth. However, the study did not measure ketone bodies and considering the type of intervention efficient ketosis is not expected. CR without limiting CHO intake hardly induces ketosis and in intermittent fasting a single daily CHO-containing meal interrupts ketogenesis. In studies examining non-ADPKD patients, similar dietary regimens only intermittently lead to very low levels of ketosis. Nevertheless,strawberry gutter system it is indeed possible that low ketone body levels potentially reached may have contributed to their findings. Whether longer-lasting KDIs have beneficial effects on TKV should be further investigated in larger studies.
A randomized controlled clinical trial on this topic is currently ongoing and another study has been announced. TLV measurements showed a significant decrease in 8/10 patients. However, after returning to a CHO-rich diet, there was a clear-cut, prompt rebound. Glucose restriction as in ketosis results in a depletion of liver glycogen stores. Considering that we only found significant changes in the non-cystic liver parenchyma this is likely to be the reason for the reversible TLV changes. In non-ADPKD patients, reductions in liver volume due to low-calorie diets have been widely described and are commonly exploited in bariatric surgery. However, a final conclusion on this topic and the effects of KDIs on cystic and noncystic liver parenchyma in ADPKD will require analyses of larger cohorts and longer-term intervention in patients with severe polycystic liver disease , also considering the fact that our study included a high proportion of patients with a very low liver cyst fraction. Consequently, it is worth further investment in this regard taking into account the complete lack of efficient therapeutic options for PLD. Rebounds of TLV have also been described after discontinuation of disease modifying drug therapy with somatostatin analogues in PLD. Hunger occurred significantly more often in the WF group, while an increased feeling of fullness was occasionally reported in the KD group. Two patients reported self-limited palpitations. Ketogenic diets can lead to prolonged QT time with an increased risk of cardiac arrhythmias. Under ketosis, regular electrocardiogram checks should be considered for patients at risk. Apart from this, no safety-relevant physical complaints, in particular no gout attacks, no kidney stones and no hypoglycemia, were observed.
We observed a statistically significant increase in total cholesterol and LDL-C in the KD group and an almost statistically significant increase of LDLC in the WF group. It is known that KDs and WF can lead to at least transient increases in LDL-C and total cholesterol, most likely through depletion of adipose lipid stores and— for KD—additionally increased intake of fatty acids. While cholesterol levels normalize after cessation of fasting, ketogenic diets have historically shown inconsistent effects on cholesterol and LDL-C levels. However, potential increases in total cholesterol and LDL-C may normalize on longer-term ketogenic diets. KDs are known to have several beneficial effects on cardiovascular disease risk, such as improvements in body weight, insulin resistance, blood pressure, HbA1c levels or inflammatory markers. Besides, the increase in LDL-C is mainly due to large LDL particles, not the more atherogenic small dense LDL particles. However, elevated LDL-C levels are a clearly defined cardiovascular risk factor in clinical practice, regardless of their sub-typing, and chronic kidney disease is a state of increased cardiovascular risk in general. Consequently, prospective long-term studies are needed to draw a definitive conclusion on the effects of a prolonged ketogenic diet on cardiovascular risk in ADPKD patients. Furthermore, there was a significant increase in uric acid resulting in a hyperuricemia in both groups after the KDIs. Increases in uric acid under ketogenic metabolism and fasting have already been described multiple times. One of the reasons for hyperuricemia is competition between BHB and uric acid for the same kidney transport sites. Uric acid levels returned to baseline after resumption of a CHO-rich diet in both groups, while no gout attacks or kidney stones were observed. Whether the increase in uric acid is clinically meaningful will require larger longer term trials. Patients at risk should be monitored during KDIs and appropriate measures, e.g. prescription of citrate, may be considered. We also detected a significant increase in serum bilirubin levels in our WF group .
Such increases upon fasting are known and considered not to be clinically relevant. The KDIs led to a significant weight loss and a reduction in body fat that persisted even after returning to a CHOrich diet. Beneficial effects of KDIs, such as improved body weight and anti-inflammatory effects, have been discussed to outweigh the possible adverse effects on CVD risk associated with cholesterol increases and have a protective role in NAFLD. Regarding ADPKD, a recent study indicated that weight reduction in overweight patients may slow the rate of kidney growth compared with historical data and obesity has been shown to be associated with disease progression. Previously reported effects of KDIs on blood pressure were not observed in our trial which may be a consequence of the short period. However, blood pressure medication had to be stopped in one patient due to a symptomatic blood pressure decrease upon starting KD. In total, 80% of all patients reached the combined feasibility and metabolic endpoint. This is in line with recent studies indicating good feasibility of KDIs in ADPKD patients. Besides, Hopp et al. recently reported good feasibility in their 1-year weight-loss trial in ADPKD patients. Some side effects of KDs, like the “keto flu,” occur mainly in the beginning. Therefore, the feasibility of KDs might be even better with longer intake and adaptation to the diet. Taken together there appears to be general good acceptance of dietary interventions among ADPKD patients.This study has several limitations: most importantly, the small number of participants needs to be considered when interpreting the results of statistical testing. Second, there was a gender imbalance, with 80% of participants being male, which limits the comparability of our data. The KDIs were of short duration. Whether longer-term KDIs thus have a more significant effect, e.g. on TKV, remains unclear. The BHB and acetone cutoffs were based on a limited amount of data. The aim of the present study was to investigate dietary interventions that can be accessible for a wide community which would not be possible if aiming for deep ketosis and stay clearly in the ketogenic range. Most investigators agree that normal BHB values are between 0.1 and 0.5 mmol/L. Since we were not aiming for deep ketosis, we therefore defined the ketosis range from a BHB value of 0.8 mmol/L, which is significantly above these values and should roughly correspond to an acetone level of 10 p.p.m. . Also, the manufacturer recommendations indicate a target ketosis range between10 and 40 p.p.m. with the cutoff to ketosis indicated as low as 5 p.p.m. acetone in breath. In conclusion,grow strawberry in containers in our proof-of-principle trial, short-term KDIs in ADPKD are safe, feasible and triggered ketosis effectively but did not show an acute impact on TKV. Larger studies are required to further investigate the potential beneficial effects of KDIs in ADPKD.Anthracnose fruit rot , caused by the fungal pathogen Colletotrichum fioriniae Marcelino & Gouli , is among the most destructive and widespread fruit disease of blueberries. The infection of C. fioriniae impacts fruit quality and can result in a complete loss of post-harvest yield. Colletotrichum species have been reported to infect numerous other high-valued fruit crops, including apple, citrus, and strawberry. Infections occur as early as fruit set but remain latent until the fruit ripens, complicating the disease’s detection and protection. Initially, sunken areas develop on the fruit surface, followed by the exudation of salmon-colored spore masses . Fungicides remain the primary method to mitigate AFR infection in cultivated blueberry. However, they are often expensive and not a favorable option for growers. Moreover, some of these fungicides are suspected carcinogens, whereas others are prone to fungicide resistance development. Often, fungicide sprays are more frequently used than necessary because of the difficulty in optimizing spray timing due to the long latency period and variable weather conditions inf luencing the pathogen life cycle. Therefore, the development of AFR-resistant cultivars is highly desired by the blueberry industry. Several highly resistant cultivars have been identified, including northern high bush Vaccinium corymbosum L. ‘Draper’, which display strong resistance in the field and in laboratory inoculation studies.
The genome of ‘Draper’ was previously sequenced for three primary reasons: it is a commonly utilized parent in breeding programs, it is widely cultivated worldwide as an early mid-season ripening variety, and it is highly resistant to AFR. However, to our knowledge, no cultivars exhibit complete resistance. In these studies, C. fioriniae had differential infection strategies and infection rates in resistant versus susceptible cultivars. Furthermore, Miles and Hancock recently reported that resistance to AFR infection is highly heritable and argue that there are likely only a few loci involved in resistance. However, the underlying genetic mechanism of resistance to AFR remains poorly understood in blueberry and other fruit crops. Blueberry fruits contain a high concentration of many phytochemicals, including compounds with known anti-fungal properties. One potential component of resistance to AFR could involve specialized metabolites. For example, quercetin 3-O-rhamnoside is a f lavonol glycoside synthesized from the amino acid precursor L-phenylalanine via the phenylpropanoid pathway whose antimicrobial activity has been demonstrated against C. fioriniae, Pseudomonas maltophilia, and Enterobacter cloacae. In fact, treating susceptible blueberry fruits with a 4% solution of extract from resistant fruit containing quercetin3-O-rhamnoside, among other anthocyanins and non-anthocyanin f lavonoids, decreased C. fioriniae infection by 88%. Quercetin and its glycosides have been studied in other systems, but the dynamics of these compounds remain poorly understood in blueberry. Quercetin glycosides may be deglycosylated, leaving the bio-active core, quercetin. Structural analysis of plantderived f lavonoids revealed that quercetin contains numerous structural components important in bioactivity against certain pathogens, including methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and Burkholderia cepacia. Furthermore, quercetin may be oxidized to form quinones, antifungal compounds previously shown to be effective against certain Colletotrichum species. However, previous studies have also proposed that AFR resistance in ripe blueberries may be due to an interaction between simple phenolic compounds and organic acids and not necessarily individual fungitoxic compounds. Here, we used a genetic mapping approach to identify genomic loci associated with resistance to AFR infection in northern high bush blueberry. We generated an RNAseq dataset to identify which genes are differentially expressed during infection in ‘Draper’ mature fruits. Finally, we performed metabolite profiling in mature fruits and identified a metabolite with properties consistent with a quercetin rhamnoside whose abundance is positively correlated with AFR resistance.AFR is a top disease priority for the blueberry industry, as it can result in up to 100% post-harvest yield loss. Thus, growers have largely relied on fungicides to maximize yields. Both the infection and resistance mechanisms of AFR are highly variable among and within crops . Resistance may arise from passive mechanisms such as physiological fruit characteristics and pre-existing compounds with anti-fungal properties. Immature fruits often exhibit many features that lend themselves to resistance to anthracnose, such as firmness, pH, and antimicrobial compounds . However, these resistance factors tend to dampen as fruit matures. Further, the accumulation of soluble sugars in conjunction with ascorbic acid was previously associated with anthracnose resistance in guava. Work in blueberry indicates a connection between sugar content and anthracnose resistance, but some moderately susceptible cultivars have high sugar concentrations. This suggests that sugar content may be only one piece of a multi-factor resistance mechanism. Additionally, the abundance of certain fruit volatiles, including -Hex-2-enal, has been linked to fruit rot resistance in strawberry. While some of these volatiles are also found in blueberry, their presence and quantity are not correlated with resistance.